Designing Library and Cover Graphics

You can definitely integrate graphics and digital photos into the design of your Adobe eBooks, especially those you create solely for viewing in Acrobat eBook Reader, Adobe Reader, or Acrobat 6. Because there is no added expense for color use in an eBook (as there is with printed books), you can feel free to embellish your eBook with colored text, borders, and fills. In addition to the graphics you might use to illustrate your eBook, you also need to consider the use of library and cover graphics. There are three different kinds of library and cover graphics: your actual eBook cover and two thumbnail versions of the eBook cover. Although none of these graphics are required to create a functioning eBook, they add to the overall look and feel of your eBook and are required if you plan to market your eBook commercially.
When specifying color conversion settings in either the Distiller or the export settings of your eBook authoring program, always choose the sRGB model. Because computer screens use the RGB model, this device-independent color setting ensures that the graphics and colors in your eBook appear accurately in a wide variety of displays.
The Cover thumbnail is used for marketing purposes when you distribute your eBook online. E-book sellers use the Cover thumbnail on their Web sites to identify and advertise your eBook. The Library thumbnail is displayed in the Acrobat eBook Reader Library, as well as the My Bookshelf feature in Adobe Reader 6 and Acrobat 6, and is used as a navigation button for selecting and opening an eBook. The actual eBook cover graphic is set as the first page in your eBook in Acrobat 6 and appears full screen (momentarily) in Acrobat eBook Reader when a user double-clicks the library thumbnail graphic to open the eBook. You can create these graphics in any editing program, though recent versions of Photoshop (5.0 and up) have the advantage of using the sRGB color model as a default.
Here are the basic specifications for these three graphics:

• Cover thumbnail: Create a thumbnail of your cover graphic in GIF format. The image should be 100 pixels wide. A 3:2 aspect ratio works well, so at that width, your image would be 150 pixels tall by 100 pixels wide. Make sure to adjust the image resolution to 96 dpi, so that the thumbnail display is sharper with fewer artifacts or pixel distortions when viewed online in a Web browser.
• Library thumbnail: The image that appears in the Acrobat eBook Reader Library is slightly different than the Cover thumbnail. For this graphic, create a thumbnail of your cover graphic in JPEG format. The image should be 100 pixels wide with the same 3:2 aspect ratio as the Cover thumbnail. Make sure to use the sRGB color model if possible (RGB otherwise) and adjust the image resolution to 96 dpi.
• eBook cover: You should also create your eBook cover in JPEG format. To fill the Acrobat eBook Reader window, it should be 600 pixels tall and 400 pixels wide, using sRGB color and 96 dpi image resolution.

The graphics and illustrations you create for the body of your eBook can be developed in any graphic or photo editing program, such as Illustrator or Photoshop. When you export your eBook to PDF, these graphics are optimized for viewing via the Distiller job option you choose during the export process. Because the Library and cover graphics are added to your eBook in Acrobat 6 after it has been exported or converted to PDF, make sure to create GIF and JPEG format graphics and use the sRGB color model so that they are fully optimized for the Web when you upload the cover thumbnail to a bookseller’s server or insert the cover and Library thumbnail in your eBook.